• 5 Posts
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Joined 1 year ago
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Cake day: June 11th, 2023

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  • instead of powering the heat pump from the wall, the heat pump can be connected directly to a PV

    I have no experience with this exact combination. I know that “batteryless” inverters exist, but most of them are on-grid inverters. In that scenario, all that matters is monitoring your production: if you don’t want grid energy, you only run your system when your PV produces enough.

    Another type of batteryless inverters are “pump inverters”. Farmers seem to like them for pumping water from wells into water towers. A pump inverter can be configured to run at 50 Hz (or 60 Hz for North Americans) and 230…240 V (or 110 V for North Americans) alright, but it is not designed to power electronic devices, but dumb agricultural motors. There is considerable risk involved with powering a heat pump from a pump inverter, unless you find an exceptionally simple and dumb heat pump with very limited or resilient steering electronics.

    Efficiency losses are small anyway, but mostly happen during battery storage or when voltage needs to rise or drop considerably (e.g. a transition of 700 -> 24 V or 24 -> 240 V would cause a small efficiency loss).

    I’ve heard that a PV can directly power a compressor

    This seems unlikely as the compressor would have to be a brushed DC motor. That kind of motors don’t last long, they wear out their brushes. Long-lasting motors are brushless, and those generally cannot be run on DC power. For example, a “brushless DC” motor is essentially a three-phased AC motor, just its controller (full of smartness and MOSFET transistors) accepts DC input.

    If you have a good technical overview of your heat pump system, maybe you can locate a point where regulated DC can be fed into the system, but that would be hacking. Alternatively, maybe a niche market already exists for DC-powered heat pumps, e.g. for caravans, trucks or ships? But on niche markets, prices typically aren’t good for you. :(


  • Relays: my use for truck relays is switching on heaters in my thermal storage water tank. Not big ones, though - I use relays rated for 24V and 40A of current. Since they are old, I have applied a safety margin and only let 25 A flow through them, so each of them handles 24 x 25 = 600 W.

    As for using DC appliances: benefits do exist. If a household has a low voltage DC battery bank (some do, some don’t) then dropping the battery voltage a few times to power car parts comes with a smaller efficiency loss. In my household, DC appliances are used for lighting, communications, computing, cooling food, pumping water and soldering electronics. The rest goes via AC. I think a car air conditioner could cool some small storage room decently. With big living rooms, it would have difficulty since it’s a small device.


  • it would (as far as i understand with high school chemistry) be strictly more efficient to electrolyse rust directly

    I’m not a chemist either, but I do know a bit of chemistry.

    Typically, you need a solution of NaOH (sodium hydroxide) to directly reduce iron oxide in an electrolysis cell. If your iron oxide contains impurities, those may react with NaOH and ruin the fun. Also, if you have exposure to CO2, your NaOH will gradually degrade, producing NaHCO3 and losing potency.

    My impression: wet electrolysis is great for making high purity iron, but it would be hard to make it work for energy storage.




  • Yep, indeed, I’m already discovering differences too. :) A good document for techies to read seems to be here.

    https://reticulum.network/manual/understanding.html

    I also think I see a problem on the horizon: announce traffic volume. According to this description, it seems that Reticulum tries to forward all announces to every transport node (router). In a small network, that’s OK. In a big network, this can become a challenge (disclaimer: I’ve participated in building I2P, but ages ago, but I still remember some stuff well enough to predict where a problem might pop up). Maintenance of the routing table / network database / <other term for a similar thing> is among the biggest challenges when things get intercontinental.


  • Interesting project, thank you for introducing. :)

    I haven’t tested anything, but only checked their specs (sadly I didn’t find out how they manage without a distributed hashtable).

    Reticulum does not use source addresses. No packets transmitted include information about the address, place, machine or person they originated from.

    Sounds like mix networks like I2P and (to a lesser degree, since its role is proxying out to the Internet) like TOR. Mix networks send traffic using the Internet, so the bottom protocol layers (TCP and UDP) use IP addresses. Higher protocol layers (end to end messages) use cryptographic identifiers.

    There is no central control over the address space in Reticulum. Anyone can allocate as many addresses as they need, when they need them.

    Sounds like TOR and I2P, but people’s convenience (easily resolving a name to an address) has created centralized resources on these nets, and will likely create similar resources on any network. An important matter is whether the central name resolver can retroactively revoke a name (in I2P for example, a name that has been already distributed is irrevocable, but you can refuse to distribute it to new nodes).

    Reticulum ensures end-to-end connectivity. Newly generated addresses become globally reachable in a matter of seconds to a few minutes.

    The same as aforementioned mix networks, but neither of them claims operability at 5 bits per second. Generally, a megabit connection is advised to meaninfully run a mix network, because you’re not expected to freeload, but help mix traffic for others (this is how the anonymity arises).

    Addresses are self-sovereign and portable. Once an address has been created, it can be moved physically to another place in the network, and continue to be reachable.

    True for TOR and I2P. The address is a public key. You can move the machine with the private key anywhere, it will build a tunnel to accept incoming traffic at some other node.

    All communication is secured with strong, modern encryption by default.

    As it should.

    All encryption keys are ephemeral, and communication offers forward secrecy by default.

    In mix networks, the keys used as endpoint addresses are not ephemeral, but permanent. I’m not sure if I should take this statement at face value. If Alice wants to speak to Bob tomorrow, some identifier of Bob must not be ephemeral.

    It is not possible to establish unencrypted links in Reticulum networks.

    Same for mix networks.

    It is not possible to send unencrypted packets to any destinations in the network.

    Same.

    Destinations receiving unencrypted packets will drop them as invalid.

    Same.

    P.S.

    I also checked their interface list and it looks reasonable. Dropping an idea too: an interface for WiFi cards in monitor/inject mode might help some people. If the tool gets popular, I’m sure someone will build it. :)



  • As an anarchist who would welcome other anarchists - sadly, I doubt if that’s a reliable recipe to stop climate change.

    Limiting (hopefully stopping) climate change can be done under almost any political system… except perhaps dictatorial petro-states. However, it takes years of work to tranform the economy. Transport, heating, food production - many things must change. Perhaps the simplest individual choices are:

    • going vegetarian (vegan if one knows enough to do the trick)
    • avoidance of using fossil fueled personal vehicles
    • improving home energy efficiency (especially in terms of heating)
    • avoidance of air travel
    • avoidance of heavy goods delivered from distant lands

    The rest - creating infrastructure to produce energy cleanly and store sufficient quantities - are typically societal choices.

    As for corals - I would start by preserving their biodiversity, sampling the genes of all coral and coral-related species and growing many of them in human-made habitats. If we’re about to cause their extinction, it’s our obligation to provide them life support until the environment has been fixed.

    Also, I would consider genetically engineering corals to tolerate higher temperatures. Since I understand that this is their critical weakness, providing a solution could save ecosystems. If a solution is feasible, that is.

    Corals reproduce sexually so a useful gene obtained from who knows where would spread among them (but slowly - because typical colonies grow bigger asexually). Also, I would keep in mind that this could have side effects.

    As for tempeature - it will be rising for some time before things can be stopped. Short of geoengineering, nothing to be done but reduce emissions, adapt, and help others adapt. The predictable outcome - it will get worse for a long while before it starts getting any better.



  • The article is mostly correct. :)

    Notes: out of the three, Latvia has serious energy storage - a 4 billion cubic meter (at normal pressure) underground gas store, sufficient to carry all three countries over the winter. So far, it’s filled with fossil natural gas - but some day it could be filled with synthesized methane.

    As a backup option, Estonia has oil shale - probably the worst fuel on Earth, so the price of emitting CO2 keeps those plants out of the energy market during summer. During winter, they come online though.

    As for solar, we aren’t planning to rely much on that. Solar capacity has of course skyrocketed, but only because it’s very easy to install. For me, it provices a nice way to charge my car from April to October. But at latitudes 55 to 60, days are really very short in midwinter, so wind and waste wood are the likely candidates in future - after oil shale leaves the scene, but before synthetic gas becomes feasible.

    Regarding pumped hydro - it can stabilize a day, but can’t stabilize a week or month. Lithuania has a biggish (~10 GWh) pumped storage facility. The rest of Baltics don’t have suitable terrain. Estonia has limestone banks, but they’re under various forms of protection and even if one built a lot of pumped hydro, the low elevation difference (up to 50 meters) means one couldn’t support the electric grid through more than a few days.

    Regarding hydrogen - maybe. But hydrogen is difficult to store, so I’m betting on wind, and on sourcing technology from Germany to produce synthetic methane from excess power during summer, and pumping it to Latvia for storage.

    Finally - connecting to the continental EU power grid allows importing energy when local wind isn’t strong enough, and exporting any surplus. So far, all three countries are still in the ex-Soviet synchronization area (common with Russia and Belarus, but with no trade, just synchronization), and thus unable to connect with the EU synchronization area. Local power companies have been building synchronous compensators (devices that steer grid frequency) for the past 2 years to drop this dependency.

    If things go as planned, Baltic countries will sever those connections and join the EU grid via Poland in winter 2025. Undersea cables already go from Estonia to Finland and Lithuania to Sweden, but in the current political conditions, I don’t think anyone counts of them for sure (a Chinese-owned but Russian-crewed ship broke the Estonia-Finland gas pipeline last autumn when dragging its anchor during a storm - it’s still unsure if the damage was accidental or not).





  • Summary:

    But then, in the geologically abrupt space of only a few decades, this great river of ice all but halted. In the two centuries since, it has moved less than 35 feet a year. According to the leading theory, the layer of water underneath it thinned, perhaps by draining into the underside of another glacier. Having lost its lubrication, the glacier slowed down and sank toward the bedrock below.

    /…/

    “The beauty of this idea is that you can start small,” Tulaczyk told me. “You can pick a puny glacier somewhere that doesn’t matter to global sea level.” This summer, Martin Truffer, a glaciologist at the University of Alaska at Fairbanks, will travel to the Juneau Icefield in Alaska to look for a small slab of ice that could be used in a pilot test. If it stops moving, Tulaczyk told me he wants to try to secure permission from Greenland’s Inuit political leaders to drain a larger glacier; he has his eye on one at the country’s northeastern edge, which discharges five gigatons of ice into the Arctic Ocean every year. Only if that worked would he move on to pilots in Antarctica.

    It’s not wild at all. :) The plan makes sense from a physical perspective, but should not be implemented lightly because:

    • it’s extremely hard work and extremely expensive to drain water from beneath an extremely large glacier
    • it doesn’t stop warming, it just puts a brake on ice loss / sea level rise

  • If the motor mount is hackable with reasonable effort, and the motor controller’s interfaces are open, then in principle… yes.

    Yet in reality, companies build extremely complicated cars where premature failure of multiple components can successfully sabotage the whole. :(

    I’ve once needed to repair a Mitsubishi EV motor controller. It took 2 days to dismantle. Schematics were far beyond my skill of reading electronics, and I build model planes as an everyday hobby, so I’ve seen electronics. Replacement of the high voltage comparator was impossible as nobody was selling it separately. The repair shop wanted to replace the entire motor controller (5000 €). Some guy from Sweden had figured out a fix: a 50 cent resistor. But installing it and putting things back was not fun at all. It wasn’t designed to be repaired.

    Needless to say, replacing a headlight bulb on the same car requires removing the front plastic cover, starting from the wheel wells, undoing six bolts, taking out the front lantern, and then you can replace the bulb. I curse them. :P

    But it drives. Hopefully long enough so I can get my own car built from scratch.



  • Interestingly, warfare also has the effect of:

    • causing houses to be abandoned, necessitating houses elsewhere while the abandoned ones likely get bombed

    • decreasing the number of future consumers, whose future footprint would depend on future behaviour patterns (hard to predict)

    • changing future land use patterns, either due to unexploded ordnance or straight out chemical contamination (there are places in France that are still off limits to economic activity, because World War I contaminated the soil with toxic chemicals), here in Estonia there are still forests from which you don’t want trees in your sawmill because they contain shrapnel and bullets from World War II

    I have the feeling that calculating the climate impact of actual war is a difficult job.

    But they could calculate the tonnage of spent fuel and energy, that would be easier.